user_script:201: attempt to compare number with nil

Hi @SGrondin,
I'm getting the following error in Redis cluster mode:
`ERR Error running script (call to f_bc60425feabe5bc26ad7ef67604a9bb0d6c03afb): @user_script:201: user_script:201: attempt to compare number with nil`

Any ideas on how I can debug this on the `bottleneck` side? 
Can I check what is on that 201st line of the Lua-script?